( 1 ) maximum output current: the current mainstream constant current source led driver chip maximum output current is about 90 ma per channel. The maximum value of constant current output per channel is more significant for the display screen because in a white balance, it is required that each channel output constant current at the same time.
( 2 ) the number of constant current output channels: constant current source output channels have 8 - bit and 16 - bit two specifications, 16 - bit mainstream, its main advantage is to reduce the chip size, easy to led driver board ( PCB ) wiring, especially for small point spacing led driver board more favorable.
( 3 ) accurate current output: one is the current error value between channels of the same chip; The other is the output current error value between different chips. Accurate current output is a key parameter, which has a great influence on the uniformity of led display. The larger the error, the worse the display uniformity, it is difficult to make the screen to achieve white balance. Bit tobit current error of mainstream constant current source chip is generally within 3 %, chip current error is within 6 %.
( 4 ) data shift clock: it determines the transmission speed of display data, and is a key indicator that affects the update rate of led display screen. As a large-size display device, the display refresh rate should be more than 85 Hz in order to ensure a stable picture ( no scanning flicker ). A higher data shift clock is the basis for the display screen to acquire a high refresh rate picture. The shift clock frequency of that main current source drive chip is generally above 15 MHz to 25 MHz.
